Instantaneous heating of a fluid circulating in a tube



Oct. 28, 1952 H. ARNAUD 2,616,022

INSTANTANEOUS, HEATING OF A FLUID CIRCULATING IN A TUBE} Filed Jan. 4,1949 s Sheets-Sheet 1 INVENTOR: HENRI ARNAUD ATTORNEY Oct. 28, 19522,616,022

INSTANTANEOUS HEATING OF A FLUID CIRCULATING IN A TUBE Filed Jan. 4,1949 H. .ARNA UD 3 Shuts-Sheet 2 IN VENTOR: HENRI HRNAUD ATTORNEY H.ARNAUD Oct. 28, 1952 INSTANTANEOUS HEATING OF A FLUID CIRCULATING IN ATUBE 3 Sheets-Sheet 3 Filed Jan. 4, 1949 I N VENTOR; HENRI ARNA upHTT'ORNEY Patented Oct. 28, 1952 OFFICE" INSTANTANEOUS, HEATING OF AFLUID CIRCULATING IN A TUBE Henri Arnaud, Paris, FranceApplicationJanuary 4, 1949, Serial No. 69,201 In France January 6, 19482 Claims.

1 Fuel oil burners require, for giving a satisfactory efficiency and aneven working, a perfect atomizing of the fuel oil condition which can beobtained only with fuel oils having a low viscosity. On the other handit is useful for a few reasons, to use heavier fuel oils which arecheaper.

The viscosity of fuel oils decreasing when the temperature increases, itis already known to previously heat them in order to bring the viscositydown to an appropriate value, the heating tem-.

the tube connected with the. nozzle as an electric heating resistance.

According to an embodiment of the invention, said portion of the tubeforms the secondary coil ofv a transformer, the primary coil of which isfed by the power of the mains.

According to another embodiment, the linear expansion of the tubefeeding and heating said fuel oil is used for actuating a switchensuring the switching off of the circuit feeding the transformer, Withthat object the tube comprises, at an appropriate point, 2, lug or stoparranged in front and at a certain distance of the member controllingthe switch, in such a way that due to the expansion of the tube, the lugor stop may come into contact with said member, and by acting upon itactuate the switch.

Means are provided for adjusting the distance, at rest, between the lugand the member controlling the switch.

The lug is for instance provided with a cam which is rotatably movableby hand.

Finally the heating device is arranged as a set or block comprising thetransformer, the part of the tube forming the heating element, theswitch of the feeding circuit and the control device of that switch,these different parts being secured on a plate and protected through aneasily detachable casing.

The invention is not relative only to the heating of fuel oil in fueloil burner devices but its scopeis extended to the instantaneous heatingof any fluid or liquid circulating in a metallic tube having a smallsection, the portion of the tube to be. heated forming, according totheinvention, a heating resistance and more particularly forming thesecondary coil of a transformer.

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The foregoing objects and advantages will be made fully apparent fromthe following descript1on reference being had to the accompanyingdrawings, and it will be understood that the devices shown are onlygiven by way of example the actual scope of the invention being deter:miFned by the appended claims.

1g. is a diagrammatic view 0 a I ofFcongentional fuel oil burner. feqmpment 1g. is a diagrammatic view of of fuel oil burner accordingto'the iriie t i Figs. 3 to 5 show different embodiments of theinvention. I

Fig. 6 is a diagrammatic trol of the switch.

Fig. 7 is a perspective diagrammatic view showing the shape of the tubto be heated e in which flows the fluid Fig. 8 shows, on a larger scale,de '0 adjusting of the distance betweeri the lifg i 1 1: switch controland the rod of said switch.

g g. iliois a side view of said device. 7

1g. is a front view of the heatin acgaordilnlg to the present invention.g apparatus 1g. is a cross-section "of Fig. 1

lmIe1 XIg-XI of said figure. along the or er to well understand the advathe device described hereafter, the equip izii 8; a burner withautomatic atomizing will be first recalled. This equipment comprises, asshown in Flg, 1, a motor driving a fuel pump a which through apressurevalve b, delivers at a constant pressure, through a tube 0, theliquid fuel toa member d called jet which atomizes said fuel the surplusfuel being returned, through tube to the inlet c1 of the pump. I v

In the embodiment shown in Fig. 2, the tube 0 feeding the fuel oil fromvalve b to jet (1 is madeof a metallic tube having a small sectioncoiled at 6 around the core of a voltage transformer f of theconventional type, and thus forms the secondary coil of saidtransformer. A copper wire 9 having a very large section connects pointsI and: sfuch a manner that the secondary and eaeormacirc' resistance.uit I g, 2, 01, I having a low The length of the tube, the number ofturns of the secondary circuit will evidently be a function of the powerto be dissipated in that tube for ensurmg the required heating. 7

view showing the con- As the resistance of the secondary circuit is verylow and the power evolved as heat is directly proportlonal to R1consequently the intensityofthe current circulating in said circuit iscon siderable. The tube will be heated through-Joules effect as soon asthe primary cell of the transformer is energized. The fuel will thusprogressively be heated from point i up to point 2. The exchange of heatbetween the fuel oil circulating in the tube and the wall of said tubeheated by J oules effect will be made easier due to the relatively highspeed of said fuel oil.

The very low calorific inertia of the portion of tube 01 and of thesmall quantity of fuel oil therein contained is such that the abovedescribed heater is a heater giving an almost instantaneous heating.

For instance, in the case of a burner which should deliver 30 litres oflight fuel per hour, heated from 10 C. to 60 C., a simple computationshows that the power evolved as heat is of about 875 watts (the totalefficiency being 60% according to an estimate).

The heating circuit may be in practice made of a 4/6 copper tube (thatis having an inner diameter of 4 millimetres and an outer diameter of 6millimetres) having a length of 1.75 metres and comprising two turns,the number of turns of the primary circuit of the transformer fed withalternating current 220 volts 50 cycles being 300.

The voltage at the secondary is about 1.6 volts which is extremely lowand gives full protection from the point of view of safety.

The regulation of the temperature of the fuel oil at point 2 may beobtained in different ways either using a transformer having a pluralityof connection contacts h with a moving handle 2', Fig. 3, and varyingthe voltage at the primary winding, or modifying the length of theheating portion 01 of tube a (Fig. 4), through a moving jaw 1c, providedat the end of wire g and which may slide on the portion of tube cconnected with valve b.

The instantaneousness of the heating of the described device has a greatadvantage in so called make-and-break burners which stop and start whenoperated by a self control (through temperature, pressure, etc. It isindeed possible to connect in parallel the motor and the primary coil ofthe transformer in order to obtain at the same time the atomizing andthe heating of the fuel.

Although the inertia of the heating device is extremely low, it ispossible to practically cancel it, when starting, by means of acontactor with an adjustable retarding device which sets the motor towork a few seconds after the primary coil of the transformer isenergized.

The closing of the secondary circuit for heating, instead of being madethrough wire 9, might be obtained through the tube for the circulationof the fuel oil which, with that object, is for instance curved as shownat 02 in Fig. 5, the curved portion being welded at the end of tubeconnected with jet d. Any other arrangement could of course be provided.

According to another embodiment, a portion of tube 0 is rectilinear asshown at 0:; (Figs. 6 and 7) and near one of the ends of thisrectilinear portion a collar or double clamp l is provided which rigidlybinds the two branches of tube 0 and thus closes the secondary circuit,in the same way as wire 9 (Figs. 2 and i) or as the welding designed inFig. 5.

Near the other end of the rectilinear portion 03' a lug or stop 8rigidly locked with the tube is provided, said lug being arranged infront of a sliding rod or lug 9 which is the member operating the switchprovided for switching off the p-ri mary coil of the transformer.

The collar 1 and the casing 10 of the switch are mounted on a samesupport, which defines a constant spacing between these two parts inspite of the expansion of the tube.

In that way, it is easy to understand that when the portion 03 of thetube increases in length. due to the expansion resulting from theheating of the tube, the lug 8 may come into contact with lug 9 and pushit in order to actuate switch 10 and thus switch off the feeding circuitof the transformer, avoiding any excessive increase of temperature. Thecircuit will be closed again when the lug 9 can, under the action of areturn spring, take back its initial position, that is when the tube iscooled enough for allowing lug 8 to be brought back to its initialposition.

The contactor I0 will be of the micro contactbreaker type (which iscommercially manufactured) and in which a displacement of a fewhundredths of a millimetre of its operating lug 9 produces a sharpbreakof current.

In order to'allow an accurate trigger action of the microcontact-breaker and to make easier the adjusting of the temperature ofthe tube above which the current should be switched off, a deviceenabling to accurately adjust the distance between lug 3 and the end oflug 9, is designed between both parts.

' With that object, the lug 8 (which is made of i a collar in twoportions 811, 8b) instead of being located immediately in front of thelug 9 of the switch, is laterally shifted with respect to that lug andbears a small cam l I (Figs. 8 and 9) ar ranged in front of said lug.That cam may be angularly moved by operating a thumb screw I2 whichprotrudes over portion 8a.. According to the angular position of thecam, the distance between said cam and lug 9 is increased or decreased.A spring [3 is designed for braking the rotation of screw I2 andconsequently of the cam in order to ensure a perfect stability of theangular position of said cam.

That cam I! may be made simply with a disc in an offset arrangement withrespect to its center of rotation, and the latter may be a screw [4rigidly locked with screw l2 and screwed in the portion 8a of lug 8. :1

According to a modification of the above embodiment, the above describedmembers are ar- Y ranged as shown in Figs. 10 and 11, in which saidmembers are mounted on a plate l5.

The whole set of the transformer, laminated core l6 and coil IT isarranged approximately at the center of plate l5. The bobbin l1comprises,

in the conventional way, several coils, and a terminal plate It enablesto insert in the circuit a variable number of these coils in order toadjust at will the intensity of the current and consequently theproduction of heat through Joules effect. One of the wires feeding thecurrent is connected to the terminal I9 which is connected through thewire 20 with one of the contacts of the micro contact-breaker It], theother contact being connected through the wire 2| with the terminal 22connected with the inlet of bobbin II.

By connecting the other wire of the feeding to 23f, it is pos-;

any one of terminals 23a, 23b sible to modify at will the intensity ofthe current, the maximum intensity being obtained by connecting thatsecond wire to terminal 23a.

tube which forms the secondary coil is arranged as shown in Figs. and11.

The jaw or double strap 7 and the stop 3a, 8b are secured to a plate 24ensuring the setting of these members with a defined spacing. This plate24 is secured to plate 15.

A cover 25 covers the whole plate i5 and ensures an emcient protectionfor the members secured to said plate. Of course holes are designed inthat cover for the passage of the connections with the ends 5 and 6 or"tube 0.

It is convenient to vertically arrange plate 15, as it is shown in thedrawing. That plate is for instance secured to a wall or to a verticalsupport, and with that object, holes 26 are designed at its upper end,said holes enabling to secure it with screws 21.

Holes 28 are designed at the upper end and at the lower end of plate l5,in order to enable the circulation of air inside of the cover. venientto cut and shape these holes in order to obtain a rounded portion asshown at 29, in such a way that these holes may be conveniently used ashandles for the handling of the apparatus.

It is to be noted that the present heater may be used to instantaneouslyheat any other fluid than fuel oil and may thus be used in otherscientific or commercial equipments.

It is also to be understood that the above shown and describedembodiments have been stated only as examples and could be modified,particularly in substituting equivalent technical means withoutdeparting from the scope of the subjoined claims.

What I claim is:

1. An electrical liquid heating apparatus comprising in combination anelectric transformer provided with means for energizing its primarywinding, a metallic tube comprising a coiled portion forming thesecondary winding of said trans- It is conare secured to establish asecondary circuit consisting of the coiled portion, connecting portion,rectilinear portion and electrically connecting means, and switch meansactuated by said lug for switching oif the current in the primarywinding of said transformer for a predetermined heat expansion .of saidrectilinear portion.

2. An electrical liquid heating apparatus comprising in combination anelectric transformer provided with means for energizing its primarywinding, a metallic tube comprising a coiled portion forming thesecondary winding of said transformer and a rectilinear portion, astationary support secured to said rectilinear portion, a lug providedwith an aperture therethrough secured to said rectilinear portion at adistance from said stationary support, means for electrically connectingtwo points of said tube respectively before said coiled portion andafter the part of said rectilinear portion to which said support and lugare secured, a pin mounted for rotation in said aperture of said lug andprovided at one end with a cam and at the other end with a thumb piece,a spring between said thumb piece and said lug for braking the rotationof said pin and ensurin a stable position of said cam, and an electricswitch in series with the primary winding of said transformer supportedby said stationary support and arranged and adapted to be actuated bysaid cam for a predetermined expansion of said rectilinear portion.

HENRI ARNAUD.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,122,892 Farrand Dec. 29, 19141,402,021 Snelling Jan. 3, 1922 1,474,777 Jarkovsky Nov. 20, 19231,513,087 Buhl et a1 Oct. 28, 1924 1,951,649 Delano Mar. 20, 19342,104,940 Woolery Jan. 11, 1938 FOREIGN PATENTS Number Country Date461,568 Germany May 31, 1928

